The development of mobile phones and portable phones and computers with an interface operating according to the Wireless Application Protocol (WAP) has increased the need for a user interface allowing a large number of options to be displayed on a small screen for selection, e.g., using a keyboard with a small number of keys.
It is well known to provide portable phones and computers with a small display screen and a small keyboard, e.g., with a navigation key to move a cursor on the display screen, so that a user is able to input data to the equipment and to select functions to be performed by the equipment. A large variety of approaches are known facilitating selection of a large number of alphanumeric characters and functions using a small keyboard together with a small screen.
For example in U.S. Pat. No. 6,016,142, a user interface is disclosed facilitating selection of a large number of characters with a 4 by 3 numeric keyboard well-known from telephones. The selectable characters are displayed on a screen in three 3 by 3 matrices located adjacent to each other. The keys “.”, “0” and “#” are used for navigation between the three matrices, activation of the “.” key causing a new alphabet to be displayed in the three matrices.
U.S. Pat. No. 5,457,454 discloses a user interface comprising a virtual keyboard. A keyboard is drawn on a screen and keys are activated by positioning a cursor at the key to be activated, e.g. with a mouse, and clicking the mouse. Characters that require more than one key to be activated in a physical keyboard are activated by positioning the cursor at the key to be activated and then drawing the key in a certain direction.
In U.S. Pat. No. 4,910,697, a keyboard with 16 keys is disclosed, wherein numerical digits can be selected with a single key activation while alphabetic characters and functions can be selected with a sequence of two key activations.
In U.S. Pat. No. 5,008,847, a user interface of a CAD system is disclosed, having a virtual keyboard with keys that are selected with a mouse controlled cursor. As in U.S. Pat. No. 4,910,697, numerical digits can be selected with a single key activation while alphabetic characters and functions can be selected with a sequence of two key activations.
EP 1 067 784 discloses a method of selecting alphanumeric characters via a remote control. A first depression of one of the buttons of the remote control causes the display on a screen of a number of segments, each segment including a plurality of letters, numbers and/or characters and an identifying number or character for each segment. The depression of the appropriate number on the remote control for the selected segment, causes the visual display to change to show the characters of the selected segment, each character positioned in a sub-segment. Subsequent depression of the appropriate number on the remote control causes the selection of the corresponding character.
EP 0 889 388 discloses a data input interface. A subset of characters is initially displayed on a touch sensor display. Respective subsets of the remaining characters of the alphabet are associated with the displayed characters. The user, having a particular character in mind, selects the displayed character associated with the subset containing the particular character. That subset is then displayed, and the user selects the desired character.
GB 2 332 293 discloses an input device for inputting instructions or data into an apparatus having a display. The display displays at least one menu item as a plurality of subsequentially selectable submenu items. Responsive to the selection of a submenu item, the display indicates the selectability of the submenu items. A selector can be used for the subsequent selection of the submenu items and data or instructions are input based on a selected menu item of submenu item.